The present invention relates to a gun for perforating a well casing and, more particularly, to a gun for supporting and detonating explosive charges in a well casing to form perforations in the casing through which water, petroleum or minerals can flow.
Perforating guns of the above type are well known and generally include a plurality of capsule charges mounted to a mounting plate, or strip, by a plurality of clips, or the like. However, these arrangements suffer from several disadvantages. For example, the mounting strip for supporting the charges is usually relatively brittle so that it will fracture into many small pieces when the charges are detonated. In addition to forming debris in the well after the explosions, the strip often breaks when it is introduced into the well. Also, the mounting strip has a relatively narrow width (in a developed view) to form a sufficient clearance between it and the inner surface of the casing. As a result, the support surface for the caps of the charge units is limited and, as a result, the caps are often separated from the mounting strip during the explosions and thus add to the debris. Further, the case of the charge unit is often connected to the cap in a manner, such as by providing cooperating threads on each, that does not secure the case to the cap sufficiently to pass fairly rigid industry standards.
Therefore, what is needed is a perforation gun which, upon firing, does not fracture prematurely and does not leave a relatively large amount of debris in the well after the explosions. Also needed is a gun of this type in which the mounting plate is provided with sufficient surface to receive the charge units in a manner to insure that the caps of the charge units will not separate from the mounting strip during the operation. In addition, a gun of this type is needed in which the case of the charge unit is firmly secured to the cap.